Annual bluegrass is a troublesome weed in turf management and there are currently limited POST herbicides labeled for use in seashore paspalum. Field and greenhouse experiments were conducted to evaluate seashore paspalum tolerance to pronamide and other herbicides for annual bluegrass control. In field experiments, turf injury never exceeded 7% from pronamide applied at dormancy, 50% green-up, or complete green-up of seashore paspalum in spring. Annual bluegrass control from pronamide was initially similar across timings and averaged 67, 90, and 98% control from 0.84, 1.68, and 3.36 kg ai ha−1, respectively, after 6 wk. In greenhouse experiments, the aforementioned pronamide rates caused less than 10% injury on seashore paspalum. Seashore paspalum injury in the greenhouse was excessive (> 20%) from atrazine, bispyribac-sodium, and trifloxysulfuron and moderate (7 to 20%) from foramsulfuron, rimsulfuron, and ethofumesate. Seashore paspalum seedhead count reductions by 4 wk after treatment (WAT) were good to excellent (87 to 98%) from atrazine, bispyribac-sodium, rimsulfuron, and trifloxysulfuron and poor (≤ 0%) from ethofumesate, foramsulfuron, and pronamide. By 4 WAT, seashore paspalum clippings were reduced 0 to 39% from pronamide, whereas atrazine, bispyribac-sodium, and trifloxysulfuron reduced clippings by 54 to 69% from the untreated and ethofumesate, foramsulfuron, and rimsulfuron reduced clippings by 27 to 39%.

Late summer goosegrass control is difficult in turfgrass as POST herbicide efficacy is reduced on mature plants. Field experiments were conducted to evaluate single and sequential nicosulfuron applications tank-mixed with foramsulfuron or sulfentrazone for late summer goosegrass control and safety to bermudagrass and seashore paspalum. All single-treatment applications controlled goosegrass < 62%, whereas sequential sulfentrazone, nicosulfuron, and nicosulfuron + sulfentrazone applications controlled goosegrass 52, 73, and 84%, respectively. Sequential foramsulfuron applications controlled goosegrass < 55% but nicosulfuron tank-mixtures did not improve control. Bermudagrass was injured < 20% by 1 and 3 wk after all single and sequential treatments. Sequential treatments of nicosulfuron alone or tank-mixed with sulfentrazone caused unacceptable seashore paspalum injury (> 20%) 1 and 3 wk after the second application, whereas foramsulfuron or sulfentrazone alone applied sequentially caused < 17% injury. Seashore paspalum seedhead control at 9 wk after intial treatment was poor (< 70%) from all single-application treatments and sequential sulfentrazone applications, but control was good (80 to 89%) to excellent (> 90%) from all other treatments. Overall, sequential treatments of nicosulfuron alone or tank-mixed with sulfentrazone appear to have potential for POST control of mature goosegrass in bermudagrass, but seashore paspalum injury was unacceptable.